[ViewVC] Diff of: cvs/IO-AIO/AIO.pm

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.211 by root, Tue Sep 27 12:10:29 2011 UTC vs.
Revision 1.287 by root, Tue Jul 24 04:58:59 2018 UTC

…		…
1	=head1 NAME	1	=head1 NAME
2		2
3	IO::AIO - Asynchronous Input/Output	3	IO::AIO - Asynchronous/Advanced Input/Output
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use IO::AIO;	7	use IO::AIO;
8		8
58	not well-supported or restricted (GNU/Linux doesn't allow them on normal	58	not well-supported or restricted (GNU/Linux doesn't allow them on normal
59	files currently, for example), and they would only support aio_read and	59	files currently, for example), and they would only support aio_read and
60	aio_write, so the remaining functionality would have to be implemented	60	aio_write, so the remaining functionality would have to be implemented
61	using threads anyway.	61	using threads anyway.
62		62
		63	In addition to asynchronous I/O, this module also exports some rather
		64	arcane interfaces, such as C<madvise> or linux's C<splice> system call,
		65	which is why the C<A> in C<AIO> can also mean I<advanced>.
		66
63	Although the module will work in the presence of other (Perl-) threads,	67	Although the module will work in the presence of other (Perl-) threads,
64	it is currently not reentrant in any way, so use appropriate locking	68	it is currently not reentrant in any way, so use appropriate locking
65	yourself, always call C<poll_cb> from within the same thread, or never	69	yourself, always call C<poll_cb> from within the same thread, or never
66	call C<poll_cb> (or other C<aio_> functions) recursively.	70	call C<poll_cb> (or other C<aio_> functions) recursively.
67		71
68	=head2 EXAMPLE	72	=head2 EXAMPLE
69		73
70	This is a simple example that uses the EV module and loads	74	This is a simple example that uses the EV module and loads
71	F</etc/passwd> asynchronously:	75	F</etc/passwd> asynchronously:
72		76
73	use Fcntl;
74	use EV;	77	use EV;
75	use IO::AIO;	78	use IO::AIO;
76		79
77	# register the IO::AIO callback with EV	80	# register the IO::AIO callback with EV
78	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;	81	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
…		…
95		98
96	# file contents now in $contents	99	# file contents now in $contents
97	print $contents;	100	print $contents;
98		101
99	# exit event loop and program	102	# exit event loop and program
100	EV::unloop;	103	EV::break;
101	};	104	};
102	};	105	};
103		106
104	# possibly queue up other requests, or open GUI windows,	107	# possibly queue up other requests, or open GUI windows,
105	# check for sockets etc. etc.	108	# check for sockets etc. etc.
106		109
107	# process events as long as there are some:	110	# process events as long as there are some:
108	EV::loop;	111	EV::run;
109		112
110	=head1 REQUEST ANATOMY AND LIFETIME	113	=head1 REQUEST ANATOMY AND LIFETIME
111		114
112	Every C<aio_*> function creates a request. which is a C data structure not	115	Every C<aio_*> function creates a request. which is a C data structure not
113	directly visible to Perl.	116	directly visible to Perl.
…		…
168	use common::sense;	171	use common::sense;
169		172
170	use base 'Exporter';	173	use base 'Exporter';
171		174
172	BEGIN {	175	BEGIN {
173	our $VERSION = '4.0';	176	our $VERSION = 4.42;
174		177
175	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close	178	our @AIO_REQ = qw(aio_sendfile aio_seek aio_read aio_write aio_open aio_close
176	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx	179	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
177	aio_scandir aio_symlink aio_readlink aio_realpath aio_sync	180	aio_scandir aio_symlink aio_readlink aio_realpath aio_fcntl aio_ioctl
178	aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_fallocate	181	aio_sync aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range
179	aio_pathsync aio_readahead	182	aio_pathsync aio_readahead aio_fiemap aio_allocate
180	aio_rename aio_link aio_move aio_copy aio_group	183	aio_rename aio_rename2 aio_link aio_move aio_copy aio_group
181	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown	184	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
182	aio_chmod aio_utime aio_truncate	185	aio_chmod aio_utime aio_truncate
183	aio_msync aio_mtouch aio_mlock aio_mlockall	186	aio_msync aio_mtouch aio_mlock aio_mlockall
184	aio_statvfs	187	aio_statvfs
		188	aio_slurp
185	aio_wd);	189	aio_wd);
186		190
187	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	191	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
188	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	192	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
189	min_parallel max_parallel max_idle idle_timeout	193	min_parallel max_parallel max_idle idle_timeout
190	nreqs nready npending nthreads	194	nreqs nready npending nthreads
191	max_poll_time max_poll_reqs	195	max_poll_time max_poll_reqs
192	sendfile fadvise madvise	196	sendfile fadvise madvise
193	mmap munmap munlock munlockall);	197	mmap munmap mremap munlock munlockall);
194		198
195	push @AIO_REQ, qw(aio_busy); # not exported	199	push @AIO_REQ, qw(aio_busy); # not exported
196		200
197	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	201	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
198		202
…		…
202		206
203	=head1 FUNCTIONS	207	=head1 FUNCTIONS
204		208
205	=head2 QUICK OVERVIEW	209	=head2 QUICK OVERVIEW
206		210
207	This section simply lists the prototypes of the most important functions	211	This section simply lists the prototypes most of the functions for
208	for quick reference. See the following sections for function-by-function	212	quick reference. See the following sections for function-by-function
209	documentation.	213	documentation.
210		214
211	aio_wd $pathname, $callback->($wd)	215	aio_wd $pathname, $callback->($wd)
212	aio_open $pathname, $flags, $mode, $callback->($fh)	216	aio_open $pathname, $flags, $mode, $callback->($fh)
213	aio_close $fh, $callback->($status)	217	aio_close $fh, $callback->($status)
		218	aio_seek $fh,$offset,$whence, $callback->($offs)
214	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	219	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
215	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	220	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
216	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	221	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
217	aio_readahead $fh,$offset,$length, $callback->($retval)	222	aio_readahead $fh,$offset,$length, $callback->($retval)
218	aio_stat $fh_or_path, $callback->($status)	223	aio_stat $fh_or_path, $callback->($status)
219	aio_lstat $fh, $callback->($status)	224	aio_lstat $fh, $callback->($status)
220	aio_statvfs $fh_or_path, $callback->($statvfs)	225	aio_statvfs $fh_or_path, $callback->($statvfs)
221	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	226	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
222	aio_chown $fh_or_path, $uid, $gid, $callback->($status)	227	aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		228	aio_chmod $fh_or_path, $mode, $callback->($status)
223	aio_truncate $fh_or_path, $offset, $callback->($status)	229	aio_truncate $fh_or_path, $offset, $callback->($status)
224	aio_chmod $fh_or_path, $mode, $callback->($status)	230	aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		231	aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
225	aio_unlink $pathname, $callback->($status)	232	aio_unlink $pathname, $callback->($status)
226	aio_mknod $pathname, $mode, $dev, $callback->($status)	233	aio_mknod $pathname, $mode, $dev, $callback->($status)
227	aio_link $srcpath, $dstpath, $callback->($status)	234	aio_link $srcpath, $dstpath, $callback->($status)
228	aio_symlink $srcpath, $dstpath, $callback->($status)	235	aio_symlink $srcpath, $dstpath, $callback->($status)
229	aio_readlink $pathname, $callback->($link)	236	aio_readlink $pathname, $callback->($link)
230	aio_realpath $pathname, $callback->($link)	237	aio_realpath $pathname, $callback->($path)
231	aio_rename $srcpath, $dstpath, $callback->($status)	238	aio_rename $srcpath, $dstpath, $callback->($status)
		239	aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
232	aio_mkdir $pathname, $mode, $callback->($status)	240	aio_mkdir $pathname, $mode, $callback->($status)
233	aio_rmdir $pathname, $callback->($status)	241	aio_rmdir $pathname, $callback->($status)
234	aio_readdir $pathname, $callback->($entries)	242	aio_readdir $pathname, $callback->($entries)
235	aio_readdirx $pathname, $flags, $callback->($entries, $flags)	243	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
236	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST	244	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
237	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN	245	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
		246	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
238	aio_load $pathname, $data, $callback->($status)	247	aio_load $pathname, $data, $callback->($status)
239	aio_copy $srcpath, $dstpath, $callback->($status)	248	aio_copy $srcpath, $dstpath, $callback->($status)
240	aio_move $srcpath, $dstpath, $callback->($status)	249	aio_move $srcpath, $dstpath, $callback->($status)
241	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
242	aio_rmtree $pathname, $callback->($status)	250	aio_rmtree $pathname, $callback->($status)
		251	aio_fcntl $fh, $cmd, $arg, $callback->($status)
		252	aio_ioctl $fh, $request, $buf, $callback->($status)
243	aio_sync $callback->($status)	253	aio_sync $callback->($status)
244	aio_syncfs $fh, $callback->($status)	254	aio_syncfs $fh, $callback->($status)
245	aio_fsync $fh, $callback->($status)	255	aio_fsync $fh, $callback->($status)
246	aio_fdatasync $fh, $callback->($status)	256	aio_fdatasync $fh, $callback->($status)
247	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	257	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
248	aio_pathsync $pathname, $callback->($status)	258	aio_pathsync $pathname, $callback->($status)
249	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	259	aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
250	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	260	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
251	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	261	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
252	aio_mlockall $flags, $callback->($status)	262	aio_mlockall $flags, $callback->($status)
253	aio_group $callback->(...)	263	aio_group $callback->(...)
254	aio_nop $callback->()	264	aio_nop $callback->()
…		…
268	IO::AIO::idle_timeout $seconds	278	IO::AIO::idle_timeout $seconds
269	IO::AIO::max_outstanding $maxreqs	279	IO::AIO::max_outstanding $maxreqs
270	IO::AIO::nreqs	280	IO::AIO::nreqs
271	IO::AIO::nready	281	IO::AIO::nready
272	IO::AIO::npending	282	IO::AIO::npending
		283	$nfd = IO::AIO::get_fdlimit [EXPERIMENTAL]
		284	IO::AIO::min_fdlimit $nfd [EXPERIMENTAL]
273		285
274	IO::AIO::sendfile $ofh, $ifh, $offset, $count	286	IO::AIO::sendfile $ofh, $ifh, $offset, $count
275	IO::AIO::fadvise $fh, $offset, $len, $advice	287	IO::AIO::fadvise $fh, $offset, $len, $advice
		288	IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
		289	IO::AIO::munmap $scalar
		290	IO::AIO::mremap $scalar, $new_length, $flags[, $new_address]
276	IO::AIO::madvise $scalar, $offset, $length, $advice	291	IO::AIO::madvise $scalar, $offset, $length, $advice
277	IO::AIO::mprotect $scalar, $offset, $length, $protect	292	IO::AIO::mprotect $scalar, $offset, $length, $protect
278	IO::AIO::munlock $scalar, $offset = 0, $length = undef	293	IO::AIO::munlock $scalar, $offset = 0, $length = undef
279	IO::AIO::munlockall	294	IO::AIO::munlockall
280		295
281	=head2 AIO REQUEST FUNCTIONS	296	=head2 API NOTES
282		297
283	All the C<aio_*> calls are more or less thin wrappers around the syscall	298	All the C<aio_*> calls are more or less thin wrappers around the syscall
284	with the same name (sans C<aio_>). The arguments are similar or identical,	299	with the same name (sans C<aio_>). The arguments are similar or identical,
285	and they all accept an additional (and optional) C<$callback> argument	300	and they all accept an additional (and optional) C<$callback> argument
286	which must be a code reference. This code reference will get called with	301	which must be a code reference. This code reference will be called after
287	the syscall return code (e.g. most syscalls return C<-1> on error, unlike	302	the syscall has been executed in an asynchronous fashion. The results
288	perl, which usually delivers "false") as its sole argument after the given	303	of the request will be passed as arguments to the callback (and, if an
289	syscall has been executed asynchronously.	304	error occured, in C<$!>) - for most requests the syscall return code (e.g.
		305	most syscalls return C<-1> on error, unlike perl, which usually delivers
		306	"false").
		307
		308	Some requests (such as C<aio_readdir>) pass the actual results and
		309	communicate failures by passing C<undef>.
290		310
291	All functions expecting a filehandle keep a copy of the filehandle	311	All functions expecting a filehandle keep a copy of the filehandle
292	internally until the request has finished.	312	internally until the request has finished.
293		313
294	All functions return request objects of type L<IO::AIO::REQ> that allow	314	All functions return request objects of type L<IO::AIO::REQ> that allow
295	further manipulation of those requests while they are in-flight.	315	further manipulation of those requests while they are in-flight.
296		316
297	The pathnames you pass to these routines I<should> be absolute. The	317	The pathnames you pass to these routines I<should> be absolute. The
298	reason for this is that at the time the request is being executed, the	318	reason for this is that at the time the request is being executed, the
299	current working directory could have changed. Alternatively, you can make	319	current working directory could have changed. Alternatively, you can
300	sure that you never change the current working directory anywhere in	320	make sure that you never change the current working directory anywhere
301	the program and then use relative paths. Lastly, you can take advantage	321	in the program and then use relative paths. You can also take advantage
302	of IO::AIOs working directory abstraction - see the description of the	322	of IO::AIOs working directory abstraction, that lets you specify paths
		323	relative to some previously-opened "working directory object" - see the
303	C<IO::AIO::WD> class later in this document.	324	description of the C<IO::AIO::WD> class later in this document.
304		325
305	To encode pathnames as octets, either make sure you either: a) always pass	326	To encode pathnames as octets, either make sure you either: a) always pass
306	in filenames you got from outside (command line, readdir etc.) without	327	in filenames you got from outside (command line, readdir etc.) without
307	tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode	328	tinkering, b) are in your native filesystem encoding, c) use the Encode
308	your pathnames to the locale (or other) encoding in effect in the user	329	module and encode your pathnames to the locale (or other) encoding in
309	environment, d) use Glib::filename_from_unicode on unicode filenames or e)	330	effect in the user environment, d) use Glib::filename_from_unicode on
310	use something else to ensure your scalar has the correct contents.	331	unicode filenames or e) use something else to ensure your scalar has the
		332	correct contents.
311		333
312	This works, btw. independent of the internal UTF-8 bit, which IO::AIO	334	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
313	handles correctly whether it is set or not.	335	handles correctly whether it is set or not.
		336
		337	=head2 AIO REQUEST FUNCTIONS
314		338
315	=over 4	339	=over 4
316		340
317	=item $prev_pri = aioreq_pri [$pri]	341	=item $prev_pri = aioreq_pri [$pri]
318		342
…		…
348		372
349		373
350	=item aio_open $pathname, $flags, $mode, $callback->($fh)	374	=item aio_open $pathname, $flags, $mode, $callback->($fh)
351		375
352	Asynchronously open or create a file and call the callback with a newly	376	Asynchronously open or create a file and call the callback with a newly
353	created filehandle for the file.	377	created filehandle for the file (or C<undef> in case of an error).
354		378
355	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,	379	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
356	for an explanation.	380	for an explanation.
357		381
358	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a	382	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
…		…
381	following POSIX and non-POSIX constants are available (missing ones on	405	following POSIX and non-POSIX constants are available (missing ones on
382	your system are, as usual, C<0>):	406	your system are, as usual, C<0>):
383		407
384	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,	408	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
385	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,	409	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
386	C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.	410	C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, C<O_TTY_INIT> and C<O_ACCMODE>.
387		411
388		412
389	=item aio_close $fh, $callback->($status)	413	=item aio_close $fh, $callback->($status)
390		414
391	Asynchronously close a file and call the callback with the result	415	Asynchronously close a file and call the callback with the result
…		…
401	Or in other words: the file descriptor will be closed, but it will not be	425	Or in other words: the file descriptor will be closed, but it will not be
402	free for reuse until the perl filehandle is closed.	426	free for reuse until the perl filehandle is closed.
403		427
404	=cut	428	=cut
405		429
		430	=item aio_seek $fh, $offset, $whence, $callback->($offs)
		431
		432	Seeks the filehandle to the new C<$offset>, similarly to perl's
		433	C<sysseek>. The C<$whence> can use the traditional values (C<0> for
		434	C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for
		435	C<IO::AIO::SEEK_END>).
		436
		437	The resulting absolute offset will be passed to the callback, or C<-1> in
		438	case of an error.
		439
		440	In theory, the C<$whence> constants could be different than the
		441	corresponding values from L<Fcntl>, but perl guarantees they are the same,
		442	so don't panic.
		443
		444	As a GNU/Linux (and maybe Solaris) extension, also the constants
		445	C<IO::AIO::SEEK_DATA> and C<IO::AIO::SEEK_HOLE> are available, if they
		446	could be found. No guarantees about suitability for use in C<aio_seek> or
		447	Perl's C<sysseek> can be made though, although I would naively assume they
		448	"just work".
		449
406	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	450	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
407		451
408	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	452	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
409		453
410	Reads or writes C<$length> bytes from or to the specified C<$fh> and	454	Reads or writes C<$length> bytes from or to the specified C<$fh> and
411	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>	455	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> and
412	and calls the callback without the actual number of bytes read (or -1 on	456	calls the callback with the actual number of bytes transferred (or -1 on
413	error, just like the syscall).	457	error, just like the syscall).
414		458
415	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to	459	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
416	offset plus the actual number of bytes read.	460	offset plus the actual number of bytes read.
417		461
…		…
475	As native sendfile syscalls (as practically any non-POSIX interface hacked	519	As native sendfile syscalls (as practically any non-POSIX interface hacked
476	together in a hurry to improve benchmark numbers) tend to be rather buggy	520	together in a hurry to improve benchmark numbers) tend to be rather buggy
477	on many systems, this implementation tries to work around some known bugs	521	on many systems, this implementation tries to work around some known bugs
478	in Linux and FreeBSD kernels (probably others, too), but that might fail,	522	in Linux and FreeBSD kernels (probably others, too), but that might fail,
479	so you really really should check the return value of C<aio_sendfile> -	523	so you really really should check the return value of C<aio_sendfile> -
480	fewre bytes than expected might have been transferred.	524	fewer bytes than expected might have been transferred.
481		525
482		526
483	=item aio_readahead $fh,$offset,$length, $callback->($retval)	527	=item aio_readahead $fh,$offset,$length, $callback->($retval)
484		528
485	C<aio_readahead> populates the page cache with data from a file so that	529	C<aio_readahead> populates the page cache with data from a file so that
…		…
489	whole pages, so that offset is effectively rounded down to a page boundary	533	whole pages, so that offset is effectively rounded down to a page boundary
490	and bytes are read up to the next page boundary greater than or equal to	534	and bytes are read up to the next page boundary greater than or equal to
491	(off-set+length). C<aio_readahead> does not read beyond the end of the	535	(off-set+length). C<aio_readahead> does not read beyond the end of the
492	file. The current file offset of the file is left unchanged.	536	file. The current file offset of the file is left unchanged.
493		537
494	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	538	If that syscall doesn't exist (likely if your kernel isn't Linux) it will
495	emulated by simply reading the data, which would have a similar effect.	539	be emulated by simply reading the data, which would have a similar effect.
496		540
497		541
498	=item aio_stat $fh_or_path, $callback->($status)	542	=item aio_stat $fh_or_path, $callback->($status)
499		543
500	=item aio_lstat $fh, $callback->($status)	544	=item aio_lstat $fh, $callback->($status)
…		…
569	namemax => 255,	613	namemax => 255,
570	frsize => 1024,	614	frsize => 1024,
571	fsid => 1810	615	fsid => 1810
572	}	616	}
573		617
574
575	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	618	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
576		619
577	Works like perl's C<utime> function (including the special case of $atime	620	Works like perl's C<utime> function (including the special case of $atime
578	and $mtime being undef). Fractional times are supported if the underlying	621	and $mtime being undef). Fractional times are supported if the underlying
579	syscalls support them.	622	syscalls support them.
…		…
606	=item aio_truncate $fh_or_path, $offset, $callback->($status)	649	=item aio_truncate $fh_or_path, $offset, $callback->($status)
607		650
608	Works like truncate(2) or ftruncate(2).	651	Works like truncate(2) or ftruncate(2).
609		652
610		653
		654	=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		655
		656	Allocates or frees disk space according to the C<$mode> argument. See the
		657	linux C<fallocate> documentation for details.
		658
		659	C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
		660	space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE \| IO::AIO::FALLOC_FL_KEEP_SIZE>,
		661	to deallocate a file range.
		662
		663	IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
		664	(without leaving a hole), C<FALLOC_FL_ZERO_RANGE>, to zero a range,
		665	C<FALLOC_FL_INSERT_RANGE> to insert a range and C<FALLOC_FL_UNSHARE_RANGE>
		666	to unshare shared blocks (see your L<fallocate(2)> manpage).
		667
		668	The file system block size used by C<fallocate> is presumably the
		669	C<f_bsize> returned by C<statvfs>, but different filesystems and filetypes
		670	can dictate other limitations.
		671
		672	If C<fallocate> isn't available or cannot be emulated (currently no
		673	emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
		674
		675
611	=item aio_chmod $fh_or_path, $mode, $callback->($status)	676	=item aio_chmod $fh_or_path, $mode, $callback->($status)
612		677
613	Works like perl's C<chmod> function.	678	Works like perl's C<chmod> function.
614		679
615		680
…		…
652		717
653		718
654	=item aio_realpath $pathname, $callback->($path)	719	=item aio_realpath $pathname, $callback->($path)
655		720
656	Asynchronously make the path absolute and resolve any symlinks in	721	Asynchronously make the path absolute and resolve any symlinks in
657	C<$path>. The resulting path only consists of directories (Same as	722	C<$path>. The resulting path only consists of directories (same as
658	L<Cwd::realpath>).	723	L<Cwd::realpath>).
659		724
660	This request can be used to get the absolute path of the current working	725	This request can be used to get the absolute path of the current working
661	directory by passing it a path of F<.> (a single dot).	726	directory by passing it a path of F<.> (a single dot).
662		727
663		728
664	=item aio_rename $srcpath, $dstpath, $callback->($status)	729	=item aio_rename $srcpath, $dstpath, $callback->($status)
665		730
666	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	731	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
667	rename(2) and call the callback with the result code.	732	rename(2) and call the callback with the result code.
		733
		734	On systems that support the AIO::WD working directory abstraction
		735	natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
		736	of failing, C<rename> is called on the absolute path of C<$wd>.
		737
		738
		739	=item aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
		740
		741	Basically a version of C<aio_rename> with an additional C<$flags>
		742	argument. Calling this with C<$flags=0> is the same as calling
		743	C<aio_rename>.
		744
		745	Non-zero flags are currently only supported on GNU/Linux systems that
		746	support renameat2. Other systems fail with C<ENOSYS> in this case.
		747
		748	The following constants are available (missing ones are, as usual C<0>),
		749	see renameat2(2) for details:
		750
		751	C<IO::AIO::RENAME_NOREPLACE>, C<IO::AIO::RENAME_EXCHANGE>
		752	and C<IO::AIO::RENAME_WHITEOUT>.
668		753
669		754
670	=item aio_mkdir $pathname, $mode, $callback->($status)	755	=item aio_mkdir $pathname, $mode, $callback->($status)
671		756
672	Asynchronously mkdir (create) a directory and call the callback with	757	Asynchronously mkdir (create) a directory and call the callback with
…		…
677	=item aio_rmdir $pathname, $callback->($status)	762	=item aio_rmdir $pathname, $callback->($status)
678		763
679	Asynchronously rmdir (delete) a directory and call the callback with the	764	Asynchronously rmdir (delete) a directory and call the callback with the
680	result code.	765	result code.
681		766
		767	On systems that support the AIO::WD working directory abstraction
		768	natively, the case C<[$wd, "."]> is specialcased - instead of failing,
		769	C<rmdir> is called on the absolute path of C<$wd>.
		770
682		771
683	=item aio_readdir $pathname, $callback->($entries)	772	=item aio_readdir $pathname, $callback->($entries)
684		773
685	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	774	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
686	directory (i.e. opendir + readdir + closedir). The entries will not be	775	directory (i.e. opendir + readdir + closedir). The entries will not be
…		…
701		790
702	=over 4	791	=over 4
703		792
704	=item IO::AIO::READDIR_DENTS	793	=item IO::AIO::READDIR_DENTS
705		794
706	When this flag is off, then the callback gets an arrayref consisting of	795	Normally the callback gets an arrayref consisting of names only (as
707	names only (as with C<aio_readdir>), otherwise it gets an arrayref with	796	with C<aio_readdir>). If this flag is set, then the callback gets an
708	C<[$name, $type, $inode]> arrayrefs, each describing a single directory	797	arrayref with C<[$name, $type, $inode]> arrayrefs, each describing a
709	entry in more detail.	798	single directory entry in more detail:
710		799
711	C<$name> is the name of the entry.	800	C<$name> is the name of the entry.
712		801
713	C<$type> is one of the C<IO::AIO::DT_xxx> constants:	802	C<$type> is one of the C<IO::AIO::DT_xxx> constants:
714		803
715	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,	804	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
716	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,	805	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
717	C<IO::AIO::DT_WHT>.	806	C<IO::AIO::DT_WHT>.
718		807
719	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to	808	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need
720	know, you have to run stat yourself. Also, for speed reasons, the C<$type>	809	to know, you have to run stat yourself. Also, for speed/memory reasons,
721	scalars are read-only: you can not modify them.	810	the C<$type> scalars are read-only: you must not modify them.
722		811
723	C<$inode> is the inode number (which might not be exact on systems with 64	812	C<$inode> is the inode number (which might not be exact on systems with 64
724	bit inode numbers and 32 bit perls). This field has unspecified content on	813	bit inode numbers and 32 bit perls). This field has unspecified content on
725	systems that do not deliver the inode information.	814	systems that do not deliver the inode information.
726		815
…		…
737	short names are tried first.	826	short names are tried first.
738		827
739	=item IO::AIO::READDIR_STAT_ORDER	828	=item IO::AIO::READDIR_STAT_ORDER
740		829
741	When this flag is set, then the names will be returned in an order	830	When this flag is set, then the names will be returned in an order
742	suitable for stat()'ing each one. That is, when you plan to stat()	831	suitable for stat()'ing each one. That is, when you plan to stat() most or
743	all files in the given directory, then the returned order will likely	832	all files in the given directory, then the returned order will likely be
744	be fastest.	833	faster.
745		834
746	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then	835	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified,
747	the likely dirs come first, resulting in a less optimal stat order.	836	then the likely dirs come first, resulting in a less optimal stat order
		837	for stat'ing all entries, but likely a more optimal order for finding
		838	subdirectories.
748		839
749	=item IO::AIO::READDIR_FOUND_UNKNOWN	840	=item IO::AIO::READDIR_FOUND_UNKNOWN
750		841
751	This flag should not be set when calling C<aio_readdirx>. Instead, it	842	This flag should not be set when calling C<aio_readdirx>. Instead, it
752	is being set by C<aio_readdirx>, when any of the C<$type>'s found were	843	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
…		…
754	C<$type>'s are known, which can be used to speed up some algorithms.	845	C<$type>'s are known, which can be used to speed up some algorithms.
755		846
756	=back	847	=back
757		848
758		849
		850	=item aio_slurp $pathname, $offset, $length, $data, $callback->($status)
		851
		852	Opens, reads and closes the given file. The data is put into C<$data>,
		853	which is resized as required.
		854
		855	If C<$offset> is negative, then it is counted from the end of the file.
		856
		857	If C<$length> is zero, then the remaining length of the file is
		858	used. Also, in this case, the same limitations to modifying C<$data> apply
		859	as when IO::AIO::mmap is used, i.e. it must only be modified in-place
		860	with C<substr>. If the size of the file is known, specifying a non-zero
		861	C<$length> results in a performance advantage.
		862
		863	This request is similar to the older C<aio_load> request, but since it is
		864	a single request, it might be more efficient to use.
		865
		866	Example: load F</etc/passwd> into C<$passwd>.
		867
		868	my $passwd;
		869	aio_slurp "/etc/passwd", 0, 0, $passwd, sub {
		870	$_[0] >= 0
		871	or die "/etc/passwd: $!\n";
		872
		873	printf "/etc/passwd is %d bytes long, and contains:\n", length $passwd;
		874	print $passwd;
		875	};
		876	IO::AIO::flush;
		877
		878
759	=item aio_load $pathname, $data, $callback->($status)	879	=item aio_load $pathname, $data, $callback->($status)
760		880
761	This is a composite request that tries to fully load the given file into	881	This is a composite request that tries to fully load the given file into
762	memory. Status is the same as with aio_read.	882	memory. Status is the same as with aio_read.
		883
		884	Using C<aio_slurp> might be more efficient, as it is a single request.
763		885
764	=cut	886	=cut
765		887
766	sub aio_load($$;$) {	888	sub aio_load($$;$) {
767	my ($path, undef, $cb) = @_;	889	my ($path, undef, $cb) = @_;
…		…
787	=item aio_copy $srcpath, $dstpath, $callback->($status)	909	=item aio_copy $srcpath, $dstpath, $callback->($status)
788		910
789	Try to copy the I<file> (directories not supported as either source or	911	Try to copy the I<file> (directories not supported as either source or
790	destination) from C<$srcpath> to C<$dstpath> and call the callback with	912	destination) from C<$srcpath> to C<$dstpath> and call the callback with
791	a status of C<0> (ok) or C<-1> (error, see C<$!>).	913	a status of C<0> (ok) or C<-1> (error, see C<$!>).
		914
		915	Existing destination files will be truncated.
792		916
793	This is a composite request that creates the destination file with	917	This is a composite request that creates the destination file with
794	mode 0200 and copies the contents of the source file into it using	918	mode 0200 and copies the contents of the source file into it using
795	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	919	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
796	uid/gid, in that order.	920	uid/gid, in that order.
…		…
906	Scans a directory (similar to C<aio_readdir>) but additionally tries to	1030	Scans a directory (similar to C<aio_readdir>) but additionally tries to
907	efficiently separate the entries of directory C<$path> into two sets of	1031	efficiently separate the entries of directory C<$path> into two sets of
908	names, directories you can recurse into (directories), and ones you cannot	1032	names, directories you can recurse into (directories), and ones you cannot
909	recurse into (everything else, including symlinks to directories).	1033	recurse into (everything else, including symlinks to directories).
910		1034
911	C<aio_scandir> is a composite request that creates of many sub requests_	1035	C<aio_scandir> is a composite request that generates many sub requests.
912	C<$maxreq> specifies the maximum number of outstanding aio requests that	1036	C<$maxreq> specifies the maximum number of outstanding aio requests that
913	this function generates. If it is C<< <= 0 >>, then a suitable default	1037	this function generates. If it is C<< <= 0 >>, then a suitable default
914	will be chosen (currently 4).	1038	will be chosen (currently 4).
915		1039
916	On error, the callback is called without arguments, otherwise it receives	1040	On error, the callback is called without arguments, otherwise it receives
…		…
967	my $grp = aio_group $cb;	1091	my $grp = aio_group $cb;
968		1092
969	$maxreq = 4 if $maxreq <= 0;	1093	$maxreq = 4 if $maxreq <= 0;
970		1094
971	# get a wd object	1095	# get a wd object
972
973	aioreq_pri $pri;	1096	aioreq_pri $pri;
974	add $grp aio_wd $path, sub {	1097	add $grp aio_wd $path, sub {
		1098	$_[0]
		1099	or return $grp->result ();
		1100
975	my $wd = [shift, "."];	1101	my $wd = [shift, "."];
976		1102
977	# stat once	1103	# stat once
978	aioreq_pri $pri;	1104	aioreq_pri $pri;
979	add $grp aio_stat $wd, sub {	1105	add $grp aio_stat $wd, sub {
…		…
1048	}	1174	}
1049		1175
1050	=item aio_rmtree $pathname, $callback->($status)	1176	=item aio_rmtree $pathname, $callback->($status)
1051		1177
1052	Delete a directory tree starting (and including) C<$path>, return the	1178	Delete a directory tree starting (and including) C<$path>, return the
1053	status of the final C<rmdir> only. This is a composite request that	1179	status of the final C<rmdir> only. This is a composite request that
1054	uses C<aio_scandir> to recurse into and rmdir directories, and unlink	1180	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1055	everything else.	1181	everything else.
1056		1182
1057	=cut	1183	=cut
1058		1184
…		…
1079	add $grp $dirgrp;	1205	add $grp $dirgrp;
1080	};	1206	};
1081		1207
1082	$grp	1208	$grp
1083	}	1209	}
		1210
		1211	=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
		1212
		1213	=item aio_ioctl $fh, $request, $buf, $callback->($status)
		1214
		1215	These work just like the C<fcntl> and C<ioctl> built-in functions, except
		1216	they execute asynchronously and pass the return value to the callback.
		1217
		1218	Both calls can be used for a lot of things, some of which make more sense
		1219	to run asynchronously in their own thread, while some others make less
		1220	sense. For example, calls that block waiting for external events, such
		1221	as locking, will also lock down an I/O thread while it is waiting, which
		1222	can deadlock the whole I/O system. At the same time, there might be no
		1223	alternative to using a thread to wait.
		1224
		1225	So in general, you should only use these calls for things that do
		1226	(filesystem) I/O, not for things that wait for other events (network,
		1227	other processes), although if you are careful and know what you are doing,
		1228	you still can.
		1229
		1230	The following constants are available (missing ones are, as usual C<0>):
		1231
		1232	C<F_DUPFD_CLOEXEC>,
		1233
		1234	C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
		1235
		1236	C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
		1237
		1238	C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
		1239	C<FS_IOC_FIEMAP>.
		1240
		1241	C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
		1242	C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
		1243
		1244	C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
		1245	C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
		1246	C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
		1247	C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
		1248	C<FS_FL_USER_MODIFIABLE>.
		1249
		1250	C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
		1251	C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
		1252	C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
		1253	C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
1084		1254
1085	=item aio_sync $callback->($status)	1255	=item aio_sync $callback->($status)
1086		1256
1087	Asynchronously call sync and call the callback when finished.	1257	Asynchronously call sync and call the callback when finished.
1088		1258
…		…
1157	};	1327	};
1158		1328
1159	$grp	1329	$grp
1160	}	1330	}
1161		1331
1162	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	1332	=item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
1163		1333
1164	This is a rather advanced IO::AIO call, which only works on mmap(2)ed	1334	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1165	scalars (see the C<IO::AIO::mmap> function, although it also works on data	1335	scalars (see the C<IO::AIO::mmap> function, although it also works on data
1166	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the	1336	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1167	scalar must only be modified in-place while an aio operation is pending on	1337	scalar must only be modified in-place while an aio operation is pending on
…		…
1169		1339
1170	It calls the C<msync> function of your OS, if available, with the memory	1340	It calls the C<msync> function of your OS, if available, with the memory
1171	area starting at C<$offset> in the string and ending C<$length> bytes	1341	area starting at C<$offset> in the string and ending C<$length> bytes
1172	later. If C<$length> is negative, counts from the end, and if C<$length>	1342	later. If C<$length> is negative, counts from the end, and if C<$length>
1173	is C<undef>, then it goes till the end of the string. The flags can be	1343	is C<undef>, then it goes till the end of the string. The flags can be
1174	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and	1344	either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional
1175	C<IO::AIO::MS_SYNC>.	1345	C<IO::AIO::MS_INVALIDATE>.
1176		1346
1177	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	1347	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1178		1348
1179	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1349	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1180	scalars.	1350	scalars.
1181		1351
1182	It touches (reads or writes) all memory pages in the specified	1352	It touches (reads or writes) all memory pages in the specified
1183	range inside the scalar. All caveats and parameters are the same	1353	range inside the scalar. All caveats and parameters are the same
1184	as for C<aio_msync>, above, except for flags, which must be either	1354	as for C<aio_msync>, above, except for flags, which must be either
1185	C<0> (which reads all pages and ensures they are instantiated) or	1355	C<0> (which reads all pages and ensures they are instantiated) or
1186	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and	1356	C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1187	writing an octet from it, which dirties the page).	1357	writing an octet from it, which dirties the page).
1188		1358
1189	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	1359	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1190		1360
1191	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1361	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
…		…
1222	documented under L<MISCELLANEOUS FUNCTIONS>.	1392	documented under L<MISCELLANEOUS FUNCTIONS>.
1223		1393
1224	Example: asynchronously lock all current and future pages into memory.	1394	Example: asynchronously lock all current and future pages into memory.
1225		1395
1226	aio_mlockall IO::AIO::MCL_FUTURE;	1396	aio_mlockall IO::AIO::MCL_FUTURE;
		1397
		1398	=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
		1399
		1400	Queries the extents of the given file (by calling the Linux C<FIEMAP>
		1401	ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
		1402	the ioctl is not available on your OS, then this request will fail with
		1403	C<ENOSYS>.
		1404
		1405	C<$start> is the starting offset to query extents for, C<$length> is the
		1406	size of the range to query - if it is C<undef>, then the whole file will
		1407	be queried.
		1408
		1409	C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
		1410	C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
		1411	exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
		1412	the data portion.
		1413
		1414	C<$count> is the maximum number of extent records to return. If it is
		1415	C<undef>, then IO::AIO queries all extents of the range. As a very special
		1416	case, if it is C<0>, then the callback receives the number of extents
		1417	instead of the extents themselves (which is unreliable, see below).
		1418
		1419	If an error occurs, the callback receives no arguments. The special
		1420	C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
		1421
		1422	Otherwise, the callback receives an array reference with extent
		1423	structures. Each extent structure is an array reference itself, with the
		1424	following members:
		1425
		1426	[$logical, $physical, $length, $flags]
		1427
		1428	Flags is any combination of the following flag values (typically either C<0>
		1429	or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
		1430
		1431	C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
		1432	C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
		1433	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
		1434	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
		1435	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
		1436	C<IO::AIO::FIEMAP_EXTENT_SHARED>.
		1437
		1438	At the time of this writing (Linux 3.2), this request is unreliable unless
		1439	C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
		1440	it to return all extents of a range for files with a large number of
		1441	extents. The code (only) works around all these issues if C<$count> is
		1442	C<undef>.
1227		1443
1228	=item aio_group $callback->(...)	1444	=item aio_group $callback->(...)
1229		1445
1230	This is a very special aio request: Instead of doing something, it is a	1446	This is a very special aio request: Instead of doing something, it is a
1231	container for other aio requests, which is useful if you want to bundle	1447	container for other aio requests, which is useful if you want to bundle
…		…
1295	object. This object stores the canonicalised, absolute version of the	1511	object. This object stores the canonicalised, absolute version of the
1296	path, and on systems that allow it, also a directory file descriptor.	1512	path, and on systems that allow it, also a directory file descriptor.
1297		1513
1298	Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>	1514	Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
1299	or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD	1515	or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
1300	object and a pathname instead. If the pathname is absolute, the	1516	object and a pathname instead (or the IO::AIO::WD object alone, which
		1517	gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the
1301	IO::AIO::WD objetc is ignored, otherwise the pathname is resolved relative	1518	IO::AIO::WD object is ignored, otherwise the pathname is resolved relative
1302	to that IO::AIO::WD object.	1519	to that IO::AIO::WD object.
1303		1520
1304	For example, to get a wd object for F</etc> and then stat F<passwd>	1521	For example, to get a wd object for F</etc> and then stat F<passwd>
1305	inside, you would write:	1522	inside, you would write:
1306		1523
…		…
1314	aio_stat [$etcdir, "passwd"], sub {	1531	aio_stat [$etcdir, "passwd"], sub {
1315	# yay	1532	# yay
1316	};	1533	};
1317	};	1534	};
1318		1535
		1536	The fact that C<aio_wd> is a request and not a normal function shows that
1319	This shows that creating an IO::AIO::WD object is itself a potentially	1537	creating an IO::AIO::WD object is itself a potentially blocking operation,
1320	blocking operation, which is why it is done asynchronously.	1538	which is why it is done asynchronously.
		1539
		1540	To stat the directory obtained with C<aio_wd> above, one could write
		1541	either of the following three request calls:
		1542
		1543	aio_lstat "/etc" , sub { ... # pathname as normal string
		1544	aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself)
		1545	aio_lstat $wd , sub { ... # shorthand for the previous
1321		1546
1322	As with normal pathnames, IO::AIO keeps a copy of the working directory	1547	As with normal pathnames, IO::AIO keeps a copy of the working directory
1323	object and the pathname string, so you could write the following without	1548	object and the pathname string, so you could write the following without
1324	causing any issues due to C<$path> getting reused:	1549	causing any issues due to C<$path> getting reused:
1325		1550
…		…
1335	There are some caveats: when directories get renamed (or deleted), the	1560	There are some caveats: when directories get renamed (or deleted), the
1336	pathname string doesn't change, so will point to the new directory (or	1561	pathname string doesn't change, so will point to the new directory (or
1337	nowhere at all), while the directory fd, if available on the system,	1562	nowhere at all), while the directory fd, if available on the system,
1338	will still point to the original directory. Most functions accepting a	1563	will still point to the original directory. Most functions accepting a
1339	pathname will use the directory fd on newer systems, and the string on	1564	pathname will use the directory fd on newer systems, and the string on
1340	older systems. Some functions (such as realpath) will always rely on the	1565	older systems. Some functions (such as C<aio_realpath>) will always rely on
1341	string form of the pathname.	1566	the string form of the pathname.
1342		1567
1343	So this fucntionality is mainly useful to get some protection against	1568	So this functionality is mainly useful to get some protection against
1344	C<chdir>, to easily get an absolute path out of a relative path for future	1569	C<chdir>, to easily get an absolute path out of a relative path for future
1345	reference, and to speed up doing many operations in the same directory	1570	reference, and to speed up doing many operations in the same directory
1346	(e.g. when stat'ing all files in a directory).	1571	(e.g. when stat'ing all files in a directory).
1347		1572
1348	The following functions implement this working directory abstraction:	1573	The following functions implement this working directory abstraction:
…		…
1361	passing C<undef> as working directory component of a pathname fails the	1586	passing C<undef> as working directory component of a pathname fails the
1362	request with C<ENOENT>, there is often no need for error checking in the	1587	request with C<ENOENT>, there is often no need for error checking in the
1363	C<aio_wd> callback, as future requests using the value will fail in the	1588	C<aio_wd> callback, as future requests using the value will fail in the
1364	expected way.	1589	expected way.
1365		1590
1366	If this call isn't available because your OS lacks it or it couldn't be
1367	detected, it will be emulated by calling C<fsync> instead.
1368
1369	=item IO::AIO::CWD	1591	=item IO::AIO::CWD
1370		1592
1371	This is a compiletime constant (object) that represents the process	1593	This is a compiletime constant (object) that represents the process
1372	current working directory.	1594	current working directory.
1373		1595
1374	Specifying this object as working directory object for a pathname is as	1596	Specifying this object as working directory object for a pathname is as if
1375	if the pathname would be specified directly, without a directory object,	1597	the pathname would be specified directly, without a directory object. For
1376	e.g., these calls are functionally identical:	1598	example, these calls are functionally identical:
1377		1599
1378	aio_stat "somefile", sub { ... };	1600	aio_stat "somefile", sub { ... };
1379	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };	1601	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1380		1602
1381	=back	1603	=back
1382		1604
		1605	To recover the path associated with an IO::AIO::WD object, you can use
		1606	C<aio_realpath>:
		1607
		1608	aio_realpath $wd, sub {
		1609	warn "path is $_[0]\n";
		1610	};
		1611
		1612	Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
		1613	sometimes, fall back to using an absolue path.
1383		1614
1384	=head2 IO::AIO::REQ CLASS	1615	=head2 IO::AIO::REQ CLASS
1385		1616
1386	All non-aggregate C<aio_*> functions return an object of this class when	1617	All non-aggregate C<aio_*> functions return an object of this class when
1387	called in non-void context.	1618	called in non-void context.
…		…
1565		1796
1566	See C<poll_cb> for an example.	1797	See C<poll_cb> for an example.
1567		1798
1568	=item IO::AIO::poll_cb	1799	=item IO::AIO::poll_cb
1569		1800
1570	Process some outstanding events on the result pipe. You have to call	1801	Process some requests that have reached the result phase (i.e. they have
		1802	been executed but the results are not yet reported). You have to call
		1803	this "regularly" to finish outstanding requests.
		1804
1571	this regularly. Returns C<0> if all events could be processed (or there	1805	Returns C<0> if all events could be processed (or there were no
1572	were no events to process), or C<-1> if it returned earlier for whatever	1806	events to process), or C<-1> if it returned earlier for whatever
1573	reason. Returns immediately when no events are outstanding. The amount of	1807	reason. Returns immediately when no events are outstanding. The amount
1574	events processed depends on the settings of C<IO::AIO::max_poll_req> and	1808	of events processed depends on the settings of C<IO::AIO::max_poll_req>,
1575	C<IO::AIO::max_poll_time>.	1809	C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
1576		1810
1577	If not all requests were processed for whatever reason, the filehandle	1811	If not all requests were processed for whatever reason, the poll file
1578	will still be ready when C<poll_cb> returns, so normally you don't have to	1812	descriptor will still be ready when C<poll_cb> returns, so normally you
1579	do anything special to have it called later.	1813	don't have to do anything special to have it called later.
1580		1814
1581	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes	1815	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1582	ready, it can be beneficial to call this function from loops which submit	1816	ready, it can be beneficial to call this function from loops which submit
1583	a lot of requests, to make sure the results get processed when they become	1817	a lot of requests, to make sure the results get processed when they become
1584	available and not just when the loop is finished and the event loop takes	1818	available and not just when the loop is finished and the event loop takes
…		…
1593	poll => 'r', async => 1,	1827	poll => 'r', async => 1,
1594	cb => \&IO::AIO::poll_cb);	1828	cb => \&IO::AIO::poll_cb);
1595		1829
1596	=item IO::AIO::poll_wait	1830	=item IO::AIO::poll_wait
1597		1831
1598	If there are any outstanding requests and none of them in the result	1832	Wait until either at least one request is in the result phase or no
1599	phase, wait till the result filehandle becomes ready for reading (simply	1833	requests are outstanding anymore.
1600	does a C<select> on the filehandle. This is useful if you want to	1834
1601	synchronously wait for some requests to finish).	1835	This is useful if you want to synchronously wait for some requests to
		1836	become ready, without actually handling them.
1602		1837
1603	See C<nreqs> for an example.	1838	See C<nreqs> for an example.
1604		1839
1605	=item IO::AIO::poll	1840	=item IO::AIO::poll
1606		1841
…		…
1727		1962
1728	This is a very bad function to use in interactive programs because it	1963	This is a very bad function to use in interactive programs because it
1729	blocks, and a bad way to reduce concurrency because it is inexact: Better	1964	blocks, and a bad way to reduce concurrency because it is inexact: Better
1730	use an C<aio_group> together with a feed callback.	1965	use an C<aio_group> together with a feed callback.
1731		1966
1732	It's main use is in scripts without an event loop - when you want to stat	1967	Its main use is in scripts without an event loop - when you want to stat
1733	a lot of files, you can write somehting like this:	1968	a lot of files, you can write something like this:
1734		1969
1735	IO::AIO::max_outstanding 32;	1970	IO::AIO::max_outstanding 32;
1736		1971
1737	for my $path (...) {	1972	for my $path (...) {
1738	aio_stat $path , ...;	1973	aio_stat $path , ...;
…		…
1777		2012
1778	=back	2013	=back
1779		2014
1780	=head3 MISCELLANEOUS FUNCTIONS	2015	=head3 MISCELLANEOUS FUNCTIONS
1781		2016
1782	IO::AIO implements some functions that might be useful, but are not	2017	IO::AIO implements some functions that are useful when you want to use
1783	asynchronous.	2018	some "Advanced I/O" function not available to in Perl, without going the
		2019	"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
		2020	counterpart.
1784		2021
1785	=over 4	2022	=over 4
		2023
		2024	=item $numfd = IO::AIO::get_fdlimit
		2025
		2026	This function is I<EXPERIMENTAL> and subject to change.
		2027
		2028	Tries to find the current file descriptor limit and returns it, or
		2029	C<undef> and sets C<$!> in case of an error. The limit is one larger than
		2030	the highest valid file descriptor number.
		2031
		2032	=item IO::AIO::min_fdlimit [$numfd]
		2033
		2034	This function is I<EXPERIMENTAL> and subject to change.
		2035
		2036	Try to increase the current file descriptor limit(s) to at least C<$numfd>
		2037	by changing the soft or hard file descriptor resource limit. If C<$numfd>
		2038	is missing, it will try to set a very high limit, although this is not
		2039	recommended when you know the actual minimum that you require.
		2040
		2041	If the limit cannot be raised enough, the function makes a best-effort
		2042	attempt to increase the limit as much as possible, using various
		2043	tricks, while still failing. You can query the resulting limit using
		2044	C<IO::AIO::get_fdlimit>.
		2045
		2046	If an error occurs, returns C<undef> and sets C<$!>, otherwise returns
		2047	true.
1786		2048
1787	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count	2049	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1788		2050
1789	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,	2051	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1790	but is blocking (this makes most sense if you know the input data is	2052	but is blocking (this makes most sense if you know the input data is
…		…
1807	=item IO::AIO::madvise $scalar, $offset, $len, $advice	2069	=item IO::AIO::madvise $scalar, $offset, $len, $advice
1808		2070
1809	Simply calls the C<posix_madvise> function (see its	2071	Simply calls the C<posix_madvise> function (see its
1810	manpage for details). The following advice constants are	2072	manpage for details). The following advice constants are
1811	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,	2073	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1812	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.	2074	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>,
		2075	C<IO::AIO::MADV_DONTNEED>.
		2076
		2077	If C<$offset> is negative, counts from the end. If C<$length> is negative,
		2078	the remaining length of the C<$scalar> is used. If possible, C<$length>
		2079	will be reduced to fit into the C<$scalar>.
1813		2080
1814	On systems that do not implement C<posix_madvise>, this function returns	2081	On systems that do not implement C<posix_madvise>, this function returns
1815	ENOSYS, otherwise the return value of C<posix_madvise>.	2082	ENOSYS, otherwise the return value of C<posix_madvise>.
1816		2083
1817	=item IO::AIO::mprotect $scalar, $offset, $len, $protect	2084	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
…		…
1819	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed	2086	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1820	$scalar (see its manpage for details). The following protect	2087	$scalar (see its manpage for details). The following protect
1821	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,	2088	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1822	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.	2089	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1823		2090
		2091	If C<$offset> is negative, counts from the end. If C<$length> is negative,
		2092	the remaining length of the C<$scalar> is used. If possible, C<$length>
		2093	will be reduced to fit into the C<$scalar>.
		2094
1824	On systems that do not implement C<mprotect>, this function returns	2095	On systems that do not implement C<mprotect>, this function returns
1825	ENOSYS, otherwise the return value of C<mprotect>.	2096	ENOSYS, otherwise the return value of C<mprotect>.
1826		2097
1827	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]	2098	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1828		2099
1829	Memory-maps a file (or anonymous memory range) and attaches it to the	2100	Memory-maps a file (or anonymous memory range) and attaches it to the
1830	given C<$scalar>, which will act like a string scalar.	2101	given C<$scalar>, which will act like a string scalar. Returns true on
		2102	success, and false otherwise.
1831		2103
		2104	The scalar must exist, but its contents do not matter - this means you
		2105	cannot use a nonexistant array or hash element. When in doubt, C<undef>
		2106	the scalar first.
		2107
1832	The only operations allowed on the scalar are C<substr>/C<vec> that don't	2108	The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
1833	change the string length, and most read-only operations such as copying it	2109	which don't change the string length, and most read-only operations such
1834	or searching it with regexes and so on.	2110	as copying it or searching it with regexes and so on.
1835		2111
1836	Anything else is unsafe and will, at best, result in memory leaks.	2112	Anything else is unsafe and will, at best, result in memory leaks.
1837		2113
1838	The memory map associated with the C<$scalar> is automatically removed	2114	The memory map associated with the C<$scalar> is automatically removed
1839	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or	2115	when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
1840	C<IO::AIO::munmap> functions are called.	2116	or C<IO::AIO::munmap> functions are called on it.
1841		2117
1842	This calls the C<mmap>(2) function internally. See your system's manual	2118	This calls the C<mmap>(2) function internally. See your system's manual
1843	page for details on the C<$length>, C<$prot> and C<$flags> parameters.	2119	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1844		2120
1845	The C<$length> must be larger than zero and smaller than the actual	2121	The C<$length> must be larger than zero and smaller than the actual
1846	filesize.	2122	filesize.
1847		2123
1848	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,	2124	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1849	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,	2125	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1850		2126
1851	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or	2127	C<$flags> can be a combination of
1852	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when	2128	C<IO::AIO::MAP_SHARED> or
1853	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>	2129	C<IO::AIO::MAP_PRIVATE>,
		2130	or a number of system-specific flags (when not available, the are C<0>):
1854	(which is set to C<MAP_ANON> if your system only provides this	2131	C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
1855	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,	2132	C<IO::AIO::MAP_LOCKED>,
1856	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or	2133	C<IO::AIO::MAP_NORESERVE>,
		2134	C<IO::AIO::MAP_POPULATE>,
1857	C<IO::AIO::MAP_NONBLOCK>	2135	C<IO::AIO::MAP_NONBLOCK>,
		2136	C<IO::AIO::MAP_FIXED>,
		2137	C<IO::AIO::MAP_GROWSDOWN>,
		2138	C<IO::AIO::MAP_32BIT>,
		2139	C<IO::AIO::MAP_HUGETLB> or
		2140	C<IO::AIO::MAP_STACK>.
1858		2141
1859	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.	2142	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1860		2143
1861	C<$offset> is the offset from the start of the file - it generally must be	2144	C<$offset> is the offset from the start of the file - it generally must be
1862	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.	2145	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
…		…
1876		2159
1877	=item IO::AIO::munmap $scalar	2160	=item IO::AIO::munmap $scalar
1878		2161
1879	Removes a previous mmap and undefines the C<$scalar>.	2162	Removes a previous mmap and undefines the C<$scalar>.
1880		2163
		2164	=item IO::AIO::mremap $scalar, $new_length, $flags = MREMAP_MAYMOVE[, $new_address = 0]
		2165
		2166	Calls the Linux-specific mremap(2) system call. The C<$scalar> must have
		2167	been mapped by C<IO::AIO::mmap>, and C<$flags> must currently either be
		2168	C<0> or C<IO::AIO::MREMAP_MAYMOVE>.
		2169
		2170	Returns true if successful, and false otherwise. If the underlying mmapped
		2171	region has changed address, then the true value has the numerical value
		2172	C<1>, otherwise it has the numerical value C<0>:
		2173
		2174	my $success = IO::AIO::mremap $mmapped, 8192, IO::AIO::MREMAP_MAYMOVE
		2175	or die "mremap: $!";
		2176
		2177	if ($success*1) {
		2178	warn "scalar has chanegd address in memory\n";
		2179	}
		2180
		2181	C<IO::AIO::MREMAP_FIXED> and the C<$new_address> argument are currently
		2182	implemented, but not supported and might go away in a future version.
		2183
		2184	On systems where this call is not supported or is not emulated, this call
		2185	returns falls and sets C<$!> to C<ENOSYS>.
		2186
1881	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef	2187	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
1882		2188
1883	Calls the C<munlock> function, undoing the effects of a previous	2189	Calls the C<munlock> function, undoing the effects of a previous
1884	C<aio_mlock> call (see its description for details).	2190	C<aio_mlock> call (see its description for details).
1885		2191
…		…
1887		2193
1888	Calls the C<munlockall> function.	2194	Calls the C<munlockall> function.
1889		2195
1890	On systems that do not implement C<munlockall>, this function returns	2196	On systems that do not implement C<munlockall>, this function returns
1891	ENOSYS, otherwise the return value of C<munlockall>.	2197	ENOSYS, otherwise the return value of C<munlockall>.
		2198
		2199	=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
		2200
		2201	Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
		2202	C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
		2203	should be the file offset.
		2204
		2205	C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
		2206	silently corrupt the data in this case.
		2207
		2208	The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
		2209	C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
		2210	C<IO::AIO::SPLICE_F_GIFT>.
		2211
		2212	See the C<splice(2)> manpage for details.
		2213
		2214	=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
		2215
		2216	Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
		2217	description for C<IO::AIO::splice> above for details.
		2218
		2219	=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
		2220
		2221	Attempts to query or change the pipe buffer size. Obviously works only
		2222	on pipes, and currently works only on GNU/Linux systems, and fails with
		2223	C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
		2224	size on other systems, drop me a note.
		2225
		2226	=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
		2227
		2228	This is a direct interface to the Linux L<pipe2(2)> system call. If
		2229	C<$flags> is missing or C<0>, then this should be the same as a call to
		2230	perl's built-in C<pipe> function and create a new pipe, and works on
		2231	systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
		2232	(..., 4096, O_BINARY)>.
		2233
		2234	If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
		2235	the given flags (Linux 2.6.27, glibc 2.9).
		2236
		2237	On success, the read and write file handles are returned.
		2238
		2239	On error, nothing will be returned. If the pipe2 syscall is missing and
		2240	C<$flags> is non-zero, fails with C<ENOSYS>.
		2241
		2242	Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
		2243	time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
		2244	C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
		2245
		2246	Example: create a pipe race-free w.r.t. threads and fork:
		2247
		2248	my ($rfh, $wfh) = IO::AIO::pipe2 IO::AIO::O_CLOEXEC
		2249	or die "pipe2: $!\n";
		2250
		2251	=item $fh = IO::AIO::eventfd [$initval, [$flags]]
		2252
		2253	This is a direct interface to the Linux L<eventfd(2)> system call. The
		2254	(unhelpful) defaults for C<$initval> and C<$flags> are C<0> for both.
		2255
		2256	On success, the new eventfd filehandle is returned, otherwise returns
		2257	C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
		2258
		2259	Please refer to L<eventfd(2)> for more info on this call.
		2260
		2261	The following symbol flag values are available: C<IO::AIO::EFD_CLOEXEC>,
		2262	C<IO::AIO::EFD_NONBLOCK> and C<IO::AIO::EFD_SEMAPHORE> (Linux 2.6.30).
		2263
		2264	Example: create a new eventfd filehandle:
		2265
		2266	$fh = IO::AIO::eventfd 0, IO::AIO::O_CLOEXEC
		2267	or die "eventfd: $!\n";
		2268
		2269	=item $fh = IO::AIO::timerfd_create $clockid[, $flags]
		2270
		2271	This is a direct interface to the Linux L<timerfd_create(2)> system call. The
		2272	(unhelpful) default for C<$flags> is C<0>.
		2273
		2274	On success, the new timerfd filehandle is returned, otherwise returns
		2275	C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
		2276
		2277	Please refer to L<timerfd_create(2)> for more info on this call.
		2278
		2279	The following C<$clockid> values are
		2280	available: C<IO::AIO::CLOCK_REALTIME>, C<IO::AIO::CLOCK_MONOTONIC>
		2281	C<IO::AIO::CLOCK_CLOCK_BOOTTIME> (Linux 3.15)
		2282	C<IO::AIO::CLOCK_CLOCK_REALTIME_ALARM> (Linux 3.11) and
		2283	C<IO::AIO::CLOCK_CLOCK_BOOTTIME_ALARM> (Linux 3.11).
		2284
		2285	The following C<$flags> values are available (Linux
		2286	2.6.27): C<IO::AIO::TFD_NONBLOCK> and C<IO::AIO::TFD_CLOEXEC>.
		2287
		2288	Example: create a new timerfd and set it to one-second repeated alarms,
		2289	then wait for two alarms:
		2290
		2291	my $fh = IO::AIO::timerfd_create IO::AIO::CLOCK_BOOTTIME, IO::AIO::TFD_CLOEXEC
		2292	or die "timerfd_create: $!\n";
		2293
		2294	defined IO::AIO::timerfd_settime $fh, 0, 1, 1
		2295	or die "timerfd_settime: $!\n";
		2296
		2297	for (1..2) {
		2298	8 == sysread $fh, my $buf, 8
		2299	or die "timerfd read failure\n";
		2300
		2301	printf "number of expirations (likely 1): %d\n",
		2302	unpack "Q", $buf;
		2303	}
		2304
		2305	=item ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value
		2306
		2307	This is a direct interface to the Linux L<timerfd_settime(2)> system
		2308	call. Please refer to its manpage for more info on this call.
		2309
		2310	The new itimerspec is specified using two (possibly fractional) second
		2311	values, C<$new_interval> and C<$new_value>).
		2312
		2313	On success, the current interval and value are returned (as per
		2314	C<timerfd_gettime>). On failure, the empty list is returned.
		2315
		2316	The following C<$flags> values are
		2317	available: C<IO::AIO::TFD_TIMER_ABSTIME> and
		2318	C<IO::AIO::TFD_TIMER_CANCEL_ON_SET>.
		2319
		2320	See C<IO::AIO::timerfd_create> for a full example.
		2321
		2322	=item ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
		2323
		2324	This is a direct interface to the Linux L<timerfd_gettime(2)> system
		2325	call. Please refer to its manpage for more info on this call.
		2326
		2327	On success, returns the current values of interval and value for the given
		2328	timerfd (as potentially fractional second values). On failure, the empty
		2329	list is returned.
1892		2330
1893	=back	2331	=back
1894		2332
1895	=cut	2333	=cut
1896		2334
…		…
1962	the process will result in undefined behaviour. Calling it at any time	2400	the process will result in undefined behaviour. Calling it at any time
1963	will also result in any undefined (by POSIX) behaviour.	2401	will also result in any undefined (by POSIX) behaviour.
1964		2402
1965	=back	2403	=back
1966		2404
		2405	=head2 LINUX-SPECIFIC CALLS
		2406
		2407	When a call is documented as "linux-specific" then this means it
		2408	originated on GNU/Linux. C<IO::AIO> will usually try to autodetect the
		2409	availability and compatibility of such calls regardless of the platform
		2410	it is compiled on, so platforms such as FreeBSD which often implement
		2411	these calls will work. When in doubt, call them and see if they fail wth
		2412	C<ENOSYS>.
		2413
1967	=head2 MEMORY USAGE	2414	=head2 MEMORY USAGE
1968		2415
1969	Per-request usage:	2416	Per-request usage:
1970		2417
1971	Each aio request uses - depending on your architecture - around 100-200	2418	Each aio request uses - depending on your architecture - around 100-200
…		…
1983	temporary buffers, and each thread requires a stack and other data	2430	temporary buffers, and each thread requires a stack and other data
1984	structures (usually around 16k-128k, depending on the OS).	2431	structures (usually around 16k-128k, depending on the OS).
1985		2432
1986	=head1 KNOWN BUGS	2433	=head1 KNOWN BUGS
1987		2434
1988	Known bugs will be fixed in the next release.	2435	Known bugs will be fixed in the next release :)
		2436
		2437	=head1 KNOWN ISSUES
		2438
		2439	Calls that try to "import" foreign memory areas (such as C<IO::AIO::mmap>
		2440	or C<IO::AIO::aio_slurp>) do not work with generic lvalues, such as
		2441	non-created hash slots or other scalars I didn't think of. It's best to
		2442	avoid such and either use scalar variables or making sure that the scalar
		2443	exists (e.g. by storing C<undef>) and isn't "funny" (e.g. tied).
		2444
		2445	I am not sure anything can be done about this, so this is considered a
		2446	known issue, rather than a bug.
1989		2447
1990	=head1 SEE ALSO	2448	=head1 SEE ALSO
1991		2449
1992	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a	2450	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
1993	more natural syntax.	2451	more natural syntax.

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.211 by root, Tue Sep 27 12:10:29 2011 UTC vs. Revision 1.287 by root, Tue Jul 24 04:58:59 2018 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.211 by root, Tue Sep 27 12:10:29 2011 UTC vs.
Revision 1.287 by root, Tue Jul 24 04:58:59 2018 UTC